Continuous mixer



April 20, 1943. w. A. cHlLsoN commuous MIXER F'iled Aug '3, 1940 WARRENA. CH/Lso/v BY v- 4 INVENTOR ATTORNEYS Patented Apr. 20, 1943 CONTINUOUSMIXER Warren A. Chilson, Niagara Falls, N. Y., assignor to MasoniteCorporation, a corporation of Delaware Application August 3; 1940,Serial No. 350,879

10 Claims.

My invention relates to a continuous mixer i'or the mixing of a liquidwith another liquid or liquids, or the mixing of liquid material withmaterial, preferably kraft pulp, air, a foaming agent or agents, such assaponin for example; for the production of strong air bubbles which canbe extensively subdivided into bubbles very minute in size, and sizingmaterials such as wax or resin size. A foamy-mix of such materialsproduced by the process of the present invention has excellent stabilityproperties and stands up well in continuous formation into sheet form,and can be dried into a relatively strong. stable sheet without materialcollapse or densification.

Qne object of the invention consists in the provision of a mixed bywhich the materials to be mixed are passed through a series of alignedannular passages, and these materials as they pass through these annularpassages are struck and crossed by outwardlydirected streams consisting01 other parts of the material to be mixed, and a very effective mixingaction is secured by the crossing streams of material produced asdescribed. I

A further object of the invention consists in the provisino of a mixerwhereby the materials to be mixed are passed through a series of annularaligned passages, while other parts of the material are being thrownoutward against and across such stream, and such thrown-out material orthe principal part thereof is returned inwardly to be repeatedly thrownoutward against and across to the streams of mix material passingthrough the annular passages.

In order to secure continuous operation, the mixer casing is preferablymade in the shape of an elongated, generally cylindrical structure, andmeans are provided for supplying materials to be mixed at one end,preferably the lower end when the casing stands vertically, anddischarged from the opposite end, preferably the upper end in case thearrangement is vertical. The passage of the materials to be mixedthrough the mixing apparatus may be effected in various ways, as bypumping for example, and the casing need not be vertical but may bearranged horizontally or in other ways. 1

The aligned annular passages through which the material is passed in thecourse of the continuous mixing thereof are provided by making thecasing of constricted form at a plurality of regions throughout thelength thereof, and utilizing such constricted casing wall parts todefine the outer walls of the annular passages. The inner walls of theannular passages are defined by impeller discs placed opposite certainof said casing constrictions, the diameter of the impeller discs beingsufflclently less than the diameter of the constricted casing parts toleave narrow annular passages therebetween.

In the accompanying drawing forming a part of this specification,

Fig. 1 is a vertical sectional view on line l-l of Fig. 2 of a mixer inaccordance with my invention; and

Fig. 2 is a transverse sectional view on line 2-2 of, Fig. 1.

The mixer of the present invention, in its preferred form, comprises acasing l0, and an impeller shaft l2 extending axially through the casingi 0 and provided with impellers I 4.

The main part of the casing is preferably made up of a series ofidentical and reversible ring-like castings it provided with flanges [8by which they may be secured together in any desired way, as for examplewith bolts, bolt holes 20 for such purpose being shown in Fig. 2. Thecasting members are of such formation as to provide the highly flattenedspheroidal chambers 22 and the constricted casing wall parts 24therebetween. A convenient way to produce the casing having suchalternate chambers 22 and constricted regions 24 therebetween is to makethese ring-like castings it of such formation that the walls of theupper half 26 of one of chambers 22 and the walls of the lower half 28of the adjacent'chamber 22 are com prised in a single casting l-li,whileproviding therebetween the inwardly directed and interiorly constrictedwall portions 24, terminating in the edges Each of the impellers l4,which are preferably made integral, as by casting, preferably comprisesa centrally disposed circular disc portion 34 and upper vanes 36 andlower vanes 38 formed thereon. These vanes may be constructed in avariety of ways, but are preferably formed as indicated in Fig. 2 so asto be adapted for effective action in throwing the mix materialsoutwardly when the impellers are rotated in the direction of the arrowon Fig. 2. Set screws and "Woodruii" keys can conveniently be used forholding the impellers I4 on shaft l2. By locating the impellers ll onthe shaft I2, opposite alternate ones of the constricted regions 2 ofthe casing ID, a series of narrow, aligned annular passages 40 isprovided between the impeller discs 34 and such constricted portions 24through which the materials of the mix are passed in streams in thecourse of their travel through the mixer. The remaining constrictedregions 24 of easing i provide freely open passages 42 between chambers22,.

so that substantially midway between the adjacent impellers and annularpassages 0 formed therearound there is a pair of such chambers 22 infree communication with one another through a passage 42.

While the ring-shaped castings l2 can advantageously be made all alikeso that they can be cast from a single or standard pattern, the endcastings of the casing are preferably specially made from anotherpattern to take care of special requirements, as the inclusion of inletsand outlets and the provision for shaft mountings, etc. However, it isdesirable to make these upper and lower castings alike to keep thestructure as simple as possible and to reduce the number of patternsrequired. In the form shown, identical upper and lower castings H, 46are therefore provided, the same containing half spheroidal chambers 26,28' and being provided with passages 4B, 50 arranged for attachment ofpipin and adapted to serve respectively the purpose of inlet and outlet,and said end castings are further provided centrally with the stuffingboxes 52, 54 through which the axial shaft I2 passes.

The drive for the impeller shaft I! in case of a vertically arrangedmixer is preferably provided at the upper end of the mixer, and this canbe accomplished by extending the shaft l2 and providing bearings 58, 60,preferably ball bearlugs, for such shaft.

A convenient way for supporting the first shaft bearing 58 is byproviding the upper end casting 46 with leg portions 62 and mountingsuch hearing 58 in the preferably cast member 64 carried by the saidlegs 62 extending upwardly from the upper end casting 46. This end ofthe mixer can be fastened to a beam or other support as by attachmentthereof to member 64. Beyond such member 64 the shaft I2 is providedwith drive means for imparting rotation to the shaft and impellers, asfor example provided with belt pulley 66. The bearing 60 provided forsteadying the shaft l2 beyond the drive pulley 68 can be supported inany desired way, as for example by being mounted in a bracket 88 boltedto the member 64. The lower end casting identical with the upper endcasting is also provided with legs 62 on which the mixer can stand.

In carrying out my improved mixing process, preferably making use ofapparatus as above described, the material is travelled through themixer, preferably by pumping in through the inlet passage 48, thispumping pressure serving also to travel the material through the mixerand to discharge the finished mix through the outlet passage 50, as forexample for supplying same to a head box from which it can becontinuously formed into a sheet. All the materials to be mixed can besupplied at 48 or the separate materials may have separate inlets ifdesired.

In their passage through the mixer the materials to be mixed aretravelled serially through the annular passages 40 in the course oftheir passage from the inlet to the outlet.

As the materials being mixed pass through these annular passages 40,they encounter cross currents produced in the material being mixed bythe rapid rotation of the impellers. These outward cross currentscreated by the rotation of the impellers and by the outward throwingaction of the impeller vanes or blades 33, 38 on the upper and lowersurfaces of the impeller discs are highly effective in producingagitation and mixing of the materials by engagement with portionsthereof passing through the annular passages 40. As shown by arrows onFig. l, the circulation within the casing between any two of theimpellers i4 is principally a vertical circulation, the material beingthrown out by the impeller vanes, striking the material passing theannular passage 40, then encountering the spheroidal walls of theadjacent chamber 22 and being directed inwardly thereby to the axialregion of the casing. The returning materials merge to some extent inthe neighborhood of the open passages 42, and this merging contributesto the securing of a uniform final mix.

In the course of being so agitated and circulated, the materialprogresses upwardly against the action of gravity so that the casing iscomnletely filled at all times, and thus through the several chambers 22under the effect of the pumping action, being finally discharged as ahomogeneous completed mix. There is also some horizontal rotationeffected by the impellers but at a much slower rate than the verticalcirculation above referred to,and indicated in Fig. 1.

In the use of my mixer and mixing process for producing a mix for themanufacture of distended fibrous sheets and wherein materials to bemixed consist principally of water and pulp, such as kraft pulp, afoaming agent such as saponin. sizing material, etc.. and largequantities of air for effecting the fiber distention, the mixer andprocess of the present invention can be used to very great advantage. Inthe mixing of such materials, it is essential that the air bubbles inthe finished mix be extremely small. Since it is impossible to introduceair into the mixer in bubbles all of small enough size, it is necessarythat these bubbles be subdivided minutely during the mixing process,this being made possible by the use of saponin or equivalent as thefoaming agent productive of strong bubble walls and making possible theminute subdivision of such'bubbles. The mixer and process of thisinvention perform this function very effectively by reason of thevigorous motion imparted to the contents and because of the rapid andfrequent change of direction of materials and portions thereof beinmixed, and by the collisions between streams moving in diversedirections and with a great variety of speeds and speed changes takingplace in the substantially incompressible liquid constitucuts of themix.

The use of a continuous mixer is of great advantage in many operations,the particular use of such mixer for affording a mix for making adistended fibrous sheet being a good example of a condition wherecontinuous mixing lsdeslrable, it being essential in forming such asheet to have a continuous source of supply of the mix so that it can beformed continuously into a sheet. As already indicated my improved mixerhas many other applications as for mixing paints and a great variety ofother mixes comprising liquid material and which may also comprisesolids and/or gases.

It is to be understood .that the illustrative showing made herein isonly for illustration and affording an understanding of principles involved, and that the invention is 'not limited thereby, being of thefull breadth defined by my claims. f

I claim:

'1. In a substantially vertically disposed mixer fed from the bottom anddischarged from the top for materials comprising liquid material, 8.casing of generally cylindrical formation except that its interior isconstricted at spaced-part zones, leaving parts of greater diameterbetween those zones, a series of rotary impellers comprising a centraldisc and upper and lower vanes, with such central disc oppositeconstructions in the be then deflected along the walls of the spheroi--casing to provide narrow but freely open annular passages therebetween,and means for travelling the materials to be mixed and including liquidmaterial through said casing against the action of gravity, said lowervanes adapted to move portions of the liquid material generallyoutwardly across the path of the traveling materials and to be thendeflected backwardly towardthe zones of greater diameter.

2. A mixer for materials comprising liquid material comprising agenerally cylindrical casing,

a series of rotary impellers axially mounted in said casing, the casingbore containing pairs of substantially flat spheroidal chambers in freecommunication with one another between adjacent impellers and beingconstricted opposite 'each impeller so as to leave a narrow annularpassage between impeller periphery and such constricted casing part, andmeans for traveling materials to be mixed including liquid materialthrough the casing and against the action of gravity, said impellersadapted to move portions of the liquid material generally outwardlyacross the path of the traveling materials and to be then deflectedalong the walls-of the spheroidal chambers.

3. A mixer for mixing materials comprising liquid material, comprising acasing'having its interior made up of a series of flattened spheroidalchambers communicating through constricted openings, an axially arrangedshaft in said casing and having a plurality of.impellers locatedopposite alternate ones of said constricted openings and of diameterless than said openings to provide narrow annular passages within saidcasing about said impellers, and means for travelling the materials tobe mixed and including liquid material through said chambers against theaction of gravity and in the course of said travel through said annularpassages. said impellers adapted to move portions of the liquid materialgenerally outwardly across the path of the traveling materials and to bethen deflected along the walls of the spheroidal chambers.

4. In a substantially vertically disposed mixer fed from the bottom anddischarged from the top for mixing materials comprising liquid material, a generally cylindrical casing having its walls made up of aseries of ring castings, each such casting containing separated halvesof flattened spheroidal chambersand an intermediate constricted part,end castings for said casing, and having inlet and outlet passages, ashaft ournalled in said end castings, said shaft being provided with aseries of impellers, each impeller comprising a central dies and upperand lower impeller vanes, and said impeller discs being located oppositealternate ones of said constricted wall portions to provide a narrowannular passage between the impeller disc and the constricted casingwall part, and the said chambers opening freely into one another at theremaining constricted wall portions. and means for traveling materialsto be mixed including liquid material through the casing and against theaction of gravity, said impeller vanes adapted to move portions of theliquid material generally outwardly across the path of the travelingmaterials and to dal chambers.

5. In a mixing apparatus, a casing formed to provide a series oftwo-part flattened substantially spheroidal chambers, said chamberscommunicating with one another through substantially circular openings,impellers revolubly mounted in the said openings, said impellerscomprising a disklike part which closes the opening except for anannular passage therearound left open for the free flow of materials tobe mixed. the said impellers having vane members at each face of thedisklike part thereof, and means for traveling materials to bemixedincluding liquid material through the casing and against the action ofgravity, said'irnpeller vanes adapted to move portions of the liquidmaterial generally outwardly across the path of the traveling materialsand to be then deflected along the walls' of the spheroidal chambers.

6. In a mixing apparatus. a casing formed to provide a. series ofchambers which are of least dimension at substantially the middleportions thereof and are of flrst increasing and then decreasingdimension toward each end, said chambers communicating with one anotherthrough substantially circular openings, andvane impellers revolublymounted in said openings, said impellers comprising a central disk ofform adapted to leave a substantially annular passage therearound forfree flow through said passage of material being mixed, and means fortraveling materials to be mixed including liquid material through thecasing and .against the action of gravity, said impeller vanes adaptedto move portions of the liquid material generally outwardly across thepath of the traveling materials and to be then deflected along the wallsof the communicating chambers.

7. In a mixing apparatus, a casing formed with chambers constricted atsubstantially the middle and enlarged at each side of the constrictedmiddie part and again constricted beyond such enlarged parts, saidchambers communicating through substantially circular openings, and impellers rotatably mounted in such openings, said impellers comprisingvane parts and a disk part which reduces said openings to an openannular passage about the disk part, and means for traveling materialsto be mixed including liquid material through the casing and against theaction of gravity, said impeller vanes adapted to move portions of theliquid material enerally outwardly across the path of the travelingmaterials and to be then deflected along the walls of the communicatingchambers.

8. In a mixing apparatus. a substantially upright casing providingchambers which are of least dimension at each end and also atsubstantially the middle and enlarged between the ends and the middleparts and communicate at their constricted ends through substantiallycircular openings, and disk and blade impellers revolubly mounted toclose said openings except for an annuiar passage therearound of widthto permit free flow of materials being mixed, and means for travelingmaterials to be mixed including liquid material through the casing andagainstthc action of gravity, said impeller blades adapted to moveportions of the liquid material generally outwardly across the path ofthe traveling materials and to be then deflected along the walls andtoward the enlarged parts of the chambers.

9. In a mixing apparatus, the combination with a generally cylindricalcasing having spacedapart regions of materially reduced diameter withinterposed outwardly rounded regions of greater diameter, of axiallymounted rotary impeller means at alternate ones of the regions ofreduced diameter and means for traveling material to be mixed lengthwisethrough the casing against the action of gravity, whereby an outwardcurrent is created crossing the lengthwise current through theregions of reduced diameter where impellers are located together with are turn current in the neighborhood of the intermediate regions ofreduced diameter.

.10. In a mixer having an intake opening at one end and a dischargeopening at the'other end for materials comprising liquid material, acasing of central disc and vanes on opposite sides of the disc, thevanes on one side of said disc being positioned toward the intakeopening and the vanes on the other side being positioned toward thedischarge opening, with such central disc opposite constrictions in thecasing to provide narrow but freely open annular passages therebetween,and means for traveling the materials to be mixed and including liquidmaterial through said casing, said vanes facing each other on successiveimpellers tending to move portions of the liquid material outwardly andthen deflected in substantial- 20 ly opposite directions.

WARREN A. CHILSON.

CERTIFICATE OF CORRECTION. Paterit No. 2,516,769. April 20, 191 5.

- mam A. CHILSON.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1,first column, line 26, for "mixed" read -mixer--; line 56, for"provisino" read -prov1sion-; page 5, first column, line 16, claim 1,for "constructions" reed --constrict1ons; line 75, claim 1;, for diceread --d1sc-; and

that the said Letters Patent should be read with this correction thereinthat the same may conform to the record of the case in the PatentOrifice.

Signed and sealed this 25th day of m A. D. 191;}.

Henry Vgm Aradale (Seal) Acting Connnisslonerof Patents.-

